LONDON (Reuters) - Small transparent spheres filled with natural or flavored water could help provide a solution to London’s plastic waste problem, according to the start-up company based in the British capital that manufactures them.

With many cities around the world struggling to dispose of vast numbers of used plastic water bottles, the biodegradable ‘Ooho balls’ have begun quenching the thirst of consumers at special events in San Francisco and London.

The balls, which resemble large bubbles, have a jelly-like membrane made of plant and seaweed extracts. The company, Skipping Rocks Lab, says the membranes decompose after four to six weeks if not consumed.

A report published by the London municipal authorities on Thursday said more than 4,000 plastic bottles had been removed from the River Thames in a one month period last year, demonstrating the scale of the waste problem.

“We think Ooho, may not be the solution for all the applications that plastic bottles have, but definitely for short term consumption it could be a solution,” Rodrigo Garcia Gonzalez, the founder of Skipping Rocks Lab, told Reuters.

In a trial near London Bridge on Wednesday, the innovative balls drew a mixture of surprise, amusement and delight among those who sampled them.

London’s city assembly said Ooho was a step forward.

“It could be part of the solution but not the only solution. You also need to be able to refill bottles at railway stations for example,” said Leonie Cooper, the Chair of the assembly’s environment committee.

Skipping Rocks, who spent three years developing Ooho, said they produce up to 2,000 balls a day but hope to increase that figure, extend the shelf-life of the product and improve the resistance of the membranes.

The company aims to target, among other consumers, marathon runners, who will be able to dispose of the Oohos mid-race without concerns about the environment. It is also considering encapsulating alcohol for a whole new market.